Installation

Version 3.2.9

Python versions

As of version 3.0.0, cfunits works for Python 3 only.

(Version 1.9 of cfunits works for Python 2 and Python 3.)

pip

To install cfunits and most of its dependencies (i.e. all except the UDUNITS library) run, for example:

Install as root, with any missing dependencies.
$ pip install cfunits
Upgrade as root, with any missing dependencies.
$ pip install cfunits --upgrade
Install as a user, with any missing dependencies.
$ pip install cfunits --user

To install cfunits without any of its dependencies then run, for example:

Install as root without installing any of the dependencies.
$ pip install cfunits --no-deps

See the documentation for pip install for further options.

Source

To install from source:

  1. Download the cfunits package from https://pypi.org/project/cfunits

  2. Unpack the library (replacing <version> with the version that you want to install, e.g. 3.0.0):

    $ tar zxvf cfunits-<version>.tar.gz
$ cd cfunits-<version>

  3. Install the package:

  • To install the cfunits package to a central location:

    $ python setup.py install

  • To install the cfunits package locally to the user in the default location:

    $ python setup.py install --user

  • To install the cfunits package in the <directory> of your choice:

    $ python setup.py install --home=<directory>

Tests

Tests are run from within the cfunits/test directory:

$ python run_tests.py

Dependencies

The cfunits package requires:

  • Python, version 3 or newer,

  • numpy, version 1.15 or newer,

  • cftime, version 1.2.1 or newer, and

  • UNIDATA UDUNITS-2 library, version 2.2.20 or newer.

    UDUNITS-2 is a C library that provides support for units of physical quantities. If the UDUNITS-2 shared library file (libudunits2.so.0 on GNU/Linux or libudunits2.0.dylibfile on MacOS) is in a non-standard location then its directory path should be added to the LD_LIBRARY_PATH environment variable. It may also be necessary to specify the location (directory path and file name) of the udunits2.xml file in the UDUNITS2_XML_PATH environment variable, although the default location is usually correct. For example, export UDUNITS2_XML_PATH=/home/user/anaconda3/share/udunits/udunits2.xml. If you get an error that looks like assert(0 == _ut_unmap_symbol_to_unit(_ut_system, _c_char_p(b'Sv'), _UT_ASCII)) then setting the UDUNITS2_XML_PATH environment variable is the likely solution.

    UDUNITS is available via Anaconda with:

    $ conda install -c conda-forge udunits2=2.2.20

Code repository

The complete source code is available at https://github.com/NCAS-CMS/cfunits